Hide a field using Listener in JIRA

[Rachel]

I want to hide a field in certain issues based on another field value selection using Listener.

I cannot use behavior as it doesn't work in all phases of an issue.

Problem statement : 

There are two fields Field A and Field B.

I want to Hide Field B when Field A == Alpha (option of field A).

[Nic Brough _Adaptavist_]

Could you explain how you think you could do this with a listener?

I am a bit stuck on the thinking behind this idea, and I don't want to second-guess anything.

I'm not sure what you mean by "Behaviour doesn't work in all phases of an issue" - what is a "phase"?  Behaviours work on screens presented by the UI, what part of it is not working?